Solid state lasers, semiconductor lasers, and gas lasers emitting light from infrared to ultraviolet wavelengths (300 to 1200 nm) have come to be easily available with high output and compact sizes. These lasers are very useful as a light source in direct-to-plate digital systems.
A diversity of studies have been undertaken on recording materials sensitive to various lasers. Recording materials hereinafter proposed typically include those writable with infrared laser light having wavelengths of 760 nm or longer, such as the positive-working material disclosed in U.S. Pat. No. 4,708,925 and the negative-working material of acid catalyst-induced crosslinking type disclosed in JP-A-8-276558 (The term “JP-A” as used herein means an “unexamined published Japanese patent application”); and those writable with ultraviolet or visible laser light having wavelengths of 300 to 700 nm, such as the radical polymerizable, negative-working materials disclosed in U.S. Pat. No. 2,850,445 and JP-B-44-20189 (the term “JP-B” as used herein means an “examined Japanese patent publication”).
On the other hand, recording materials sensitive to short wavelengths of 300 nm or shorter and electron rays are specially important as a photoresist material. With the recent increase in integrity of integrated circuits, micro-patterning technology achieving half micron or finer line widths has been demanded in the fabrication of semiconductor substrates for VLSIs, etc. To meet the demand, the wavelengths of aligners used in photolithography have been getting shorter and shorter. Use of far ultraviolet light or excimer laser light (e.g., XeCl, KrF or ArF) has been attempted, and supermicro-patterning with an electron beam has now come to be studied. In particular, an electron beam is a promising light source for patterning technology of next generation.
Performance requirements common to all these image-forming materials are film strength, storage stability, and high sensitivity of a photosensitive layer. Recording materials for lithographic printing plates are especially required to have high film strength for assuring press life. However, it is difficult to satisfy all the requirements for film strength, storage stability and sensitivity. State-of-the art image-forming materials have not shown sufficiently satisfactory results, waiting for development of innovative techniques.